/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file game_text.cpp Implementation of handling translated strings. */

#include "../stdafx.h"
#include "../strgen/strgen.h"
#include "../debug.h"
#include "../fileio_func.h"
#include "../tar_type.h"
#include "../script/squirrel_class.hpp"
#include "../strings_func.h"
#include "game_text.hpp"
#include "game.hpp"
#include "game_info.hpp"

#include "table/strings.h"

#include <stdarg.h>
#include <memory>

#include "../safeguards.h"

void CDECL strgen_warning(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vseprintf(buf, lastof(buf), s, va);
	va_end(va);
	DEBUG(script, 0, "%s:%d: warning: %s", _file, _cur_line, buf);
	_warnings++;
}

void CDECL strgen_error(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vseprintf(buf, lastof(buf), s, va);
	va_end(va);
	DEBUG(script, 0, "%s:%d: error: %s", _file, _cur_line, buf);
	_errors++;
}

void NORETURN CDECL strgen_fatal(const char *s, ...)
{
	char buf[1024];
	va_list va;
	va_start(va, s);
	vseprintf(buf, lastof(buf), s, va);
	va_end(va);
	DEBUG(script, 0, "%s:%d: FATAL: %s", _file, _cur_line, buf);
	throw std::exception();
}

/**
 * Create a new container for language strings.
 * @param language The language name.
 * @param end If not nullptr, terminate \a language at this position.
 */
LanguageStrings::LanguageStrings(const char *language, const char *end)
{
	this->language = stredup(language, end != nullptr ? end - 1 : nullptr);
}

/** Free everything. */
LanguageStrings::~LanguageStrings()
{
	free(this->language);
}

/**
 * Read all the raw language strings from the given file.
 * @param file The file to read from.
 * @return The raw strings, or nullptr upon error.
 */
std::unique_ptr<LanguageStrings> ReadRawLanguageStrings(const char *file)
{
	try {
		size_t to_read;
		FILE *fh = FioFOpenFile(file, "rb", GAME_DIR, &to_read);
		if (fh == nullptr) return nullptr;

		FileCloser fhClose(fh);

		const char *langname = strrchr(file, PATHSEPCHAR);
		if (langname == nullptr) {
			langname = file;
		} else {
			langname++;
		}

		/* Check for invalid empty filename */
		if (*langname == '.' || *langname == 0) return nullptr;

		std::unique_ptr<LanguageStrings> ret(new LanguageStrings(langname, strchr(langname, '.')));

		char buffer[2048];
		while (to_read != 0 && fgets(buffer, sizeof(buffer), fh) != nullptr) {
			size_t len = strlen(buffer);

			/* Remove trailing spaces/newlines from the string. */
			size_t i = len;
			while (i > 0 && (buffer[i - 1] == '\r' || buffer[i - 1] == '\n' || buffer[i - 1] == ' ')) i--;
			buffer[i] = '\0';

			ret->lines.emplace_back(buffer, i);

			if (len > to_read) {
				to_read = 0;
			} else {
				to_read -= len;
			}
		}

		return ret;
	} catch (...) {
		return nullptr;
	}
}


/** A reader that simply reads using fopen. */
struct StringListReader : StringReader {
	StringList::const_iterator p;   ///< The current location of the iteration.
	StringList::const_iterator end; ///< The end of the iteration.

	/**
	 * Create the reader.
	 * @param data        The data to fill during reading.
	 * @param strings     The language strings we are reading.
	 * @param master      Are we reading the master file?
	 * @param translation Are we reading a translation?
	 */
	StringListReader(StringData &data, const LanguageStrings &strings, bool master, bool translation) :
			StringReader(data, strings.language, master, translation), p(strings.lines.begin()), end(strings.lines.end())
	{
	}

	char *ReadLine(char *buffer, const char *last) override
	{
		if (this->p == this->end) return nullptr;

		strecpy(buffer, this->p->c_str(), last);
		this->p++;

		return buffer;
	}
};

/** Class for writing an encoded language. */
struct TranslationWriter : LanguageWriter {
	StringList &strings; ///< The encoded strings.

	/**
	 * Writer for the encoded data.
	 * @param strings The string table to add the strings to.
	 */
	TranslationWriter(StringList &strings) : strings(strings)
	{
	}

	void WriteHeader(const LanguagePackHeader *header)
	{
		/* We don't use the header. */
	}

	void Finalise()
	{
		/* Nothing to do. */
	}

	void WriteLength(uint length)
	{
		/* We don't write the length. */
	}

	void Write(const byte *buffer, size_t length)
	{
		this->strings.emplace_back((const char *)buffer, length);
	}
};

/** Class for writing the string IDs. */
struct StringNameWriter : HeaderWriter {
	StringList &strings; ///< The string names.

	/**
	 * Writer for the string names.
	 * @param strings The string table to add the strings to.
	 */
	StringNameWriter(StringList &strings) : strings(strings)
	{
	}

	void WriteStringID(const char *name, int stringid)
	{
		if (stringid == (int)this->strings.size()) this->strings.emplace_back(name);
	}

	void Finalise(const StringData &data)
	{
		/* Nothing to do. */
	}
};

/**
 * Scanner to find language files in a GameScript directory.
 */
class LanguageScanner : protected FileScanner {
private:
	GameStrings *gs;
	char *exclude;

public:
	/** Initialise */
	LanguageScanner(GameStrings *gs, const char *exclude) : gs(gs), exclude(stredup(exclude)) {}
	~LanguageScanner() { free(exclude); }

	/**
	 * Scan.
	 */
	void Scan(const char *directory)
	{
		this->FileScanner::Scan(".txt", directory, false);
	}

	bool AddFile(const char *filename, size_t basepath_length, const char *tar_filename) override
	{
		if (strcmp(filename, exclude) == 0) return true;

		auto ls = ReadRawLanguageStrings(filename);
		if (ls == nullptr) return false;

		gs->raw_strings.push_back(std::move(ls));
		return true;
	}
};

/**
 * Load all translations that we know of.
 * @return Container with all (compiled) translations.
 */
GameStrings *LoadTranslations()
{
	const GameInfo *info = Game::GetInfo();
	char filename[512];
	strecpy(filename, info->GetMainScript(), lastof(filename));
	char *e = strrchr(filename, PATHSEPCHAR);
	if (e == nullptr) return nullptr;
	e++; // Make 'e' point after the PATHSEPCHAR

	strecpy(e, "lang" PATHSEP "english.txt", lastof(filename));
	if (!FioCheckFileExists(filename, GAME_DIR)) return nullptr;

	auto ls = ReadRawLanguageStrings(filename);
	if (ls == nullptr) return nullptr;

	GameStrings *gs = new GameStrings();
	try {
		gs->raw_strings.push_back(std::move(ls));

		/* Scan for other language files */
		LanguageScanner scanner(gs, filename);
		strecpy(e, "lang" PATHSEP, lastof(filename));
		size_t len = strlen(filename);

		const char *tar_filename = info->GetTarFile();
		TarList::iterator iter;
		if (tar_filename != nullptr && (iter = _tar_list[GAME_DIR].find(tar_filename)) != _tar_list[GAME_DIR].end()) {
			/* The main script is in a tar file, so find all files that
			 * are in the same tar and add them to the langfile scanner. */
			TarFileList::iterator tar;
			FOR_ALL_TARS(tar, GAME_DIR) {
				/* Not in the same tar. */
				if (tar->second.tar_filename != iter->first) continue;

				/* Check the path and extension. */
				if (tar->first.size() <= len || tar->first.compare(0, len, filename) != 0) continue;
				if (tar->first.compare(tar->first.size() - 4, 4, ".txt") != 0) continue;

				scanner.AddFile(tar->first.c_str(), 0, tar_filename);
			}
		} else {
			/* Scan filesystem */
			scanner.Scan(filename);
		}

		gs->Compile();
		return gs;
	} catch (...) {
		delete gs;
		return nullptr;
	}
}

/** Compile the language. */
void GameStrings::Compile()
{
	StringData data(32);
	StringListReader master_reader(data, *this->raw_strings[0], true, false);
	master_reader.ParseFile();
	if (_errors != 0) throw std::exception();

	this->version = data.Version();

	StringNameWriter id_writer(this->string_names);
	id_writer.WriteHeader(data);

	for (const auto &p : this->raw_strings) {
		data.FreeTranslation();
		StringListReader translation_reader(data, *p, false, strcmp(p->language, "english") != 0);
		translation_reader.ParseFile();
		if (_errors != 0) throw std::exception();

		this->compiled_strings.emplace_back(new LanguageStrings(p->language));
		TranslationWriter writer(this->compiled_strings.back()->lines);
		writer.WriteLang(data);
	}
}

/** The currently loaded game strings. */
GameStrings *_current_data = nullptr;

/**
 * Get the string pointer of a particular game string.
 * @param id The ID of the game string.
 * @return The encoded string.
 */
const char *GetGameStringPtr(uint id)
{
	if (id >= _current_data->cur_language->lines.size()) return GetStringPtr(STR_UNDEFINED);
	return _current_data->cur_language->lines[id].c_str();
}

/**
 * Register the current translation to the Squirrel engine.
 * @param engine The engine to update/
 */
void RegisterGameTranslation(Squirrel *engine)
{
	delete _current_data;
	_current_data = LoadTranslations();
	if (_current_data == nullptr) return;

	HSQUIRRELVM vm = engine->GetVM();
	sq_pushroottable(vm);
	sq_pushstring(vm, "GSText", -1);
	if (SQ_FAILED(sq_get(vm, -2))) return;

	int idx = 0;
	for (const auto &p : _current_data->string_names) {
		sq_pushstring(vm, p.c_str(), -1);
		sq_pushinteger(vm, idx);
		sq_rawset(vm, -3);
		idx++;
	}

	sq_pop(vm, 2);

	ReconsiderGameScriptLanguage();
}

/**
 * Reconsider the game script language, so we use the right one.
 */
void ReconsiderGameScriptLanguage()
{
	if (_current_data == nullptr) return;

	char temp[MAX_PATH];
	strecpy(temp, _current_language->file, lastof(temp));

	/* Remove the extension */
	char *l = strrchr(temp, '.');
	assert(l != nullptr);
	*l = '\0';

	/* Skip the path */
	char *language = strrchr(temp, PATHSEPCHAR);
	assert(language != nullptr);
	language++;

	for (auto &p : _current_data->compiled_strings) {
		if (strcmp(p->language, language) == 0) {
			_current_data->cur_language = p;
			return;
		}
	}

	_current_data->cur_language = _current_data->compiled_strings[0];
}